Put the crumble ingredients in a food processor and pulse about 25 times, or until it resembles coarse crumbs. Pour it into a bowl, add the vanilla paste, and work it in with your fingers, I like to create some clumps in the mixture with my fingers by pressing it together to get a coarser crumble texture.
Whisk together the sugar, flour, and cornstarch for the filling in a large bowl. Add the fruit and toss to get it all coated with the flour sugar mixture.
Transfer your frozen pie crust to one of your own pie plates if you like. Fill the frozen pie crust with the fruit filling. Top with the crumble topping.
Put the pie on a baking sheet and bake for 50-60 minutes until golden and bubbling. Check the pie half way through and if it seems to be browning too quickly, lay a piece of foil loosely over the top.
Let the pie cool before slicing ~ when the filling is still hot it will be very runny.
Notes
*Apple is rich in natural pectin and helps thicken the pie filling.